1. Field of the Invention
The invention relates generally to weatherstrips for motor vehicles and more specifically to a mechanically interlocked weatherstrip for window frames of a motor vehicle.
2. Related Art
Most motor vehicles are equipped with movable windows that slide in a window opening from an up or extended position that seals off the opening to a down position, retracted within the vehicle body, that opens all or a portion of the opening and allows an exchange of air between the inside and outside of the vehicle. A sealing device broadly referred to as a weatherstrip is disposed about the periphery of the window opening and provides an air and watertight seal between the vehicle body and the window. The interface between the body and the movable window at the lower extremity of the window opening is typically equipped with a weatherstrip denominated a beltstrip which aesthetically hides the interface and provides a wiper flange or blade for cleaning the window as the window extends and retracts from the body of the vehicle.
Recently, emphasis has been placed upon vehicle streamlining for drag reduction purposes and reduction of wind noise. To achieve these goals, design considerations such as the elimination of all gaps and channels, low profile configurations, overlapping of the beltstrip or weatherstrip on the glass for wind noise reduction, as well as installation ease, serviceability and durability have greatly increased significance. The challenge of achieving such goals depends upon the proper execution of such design considerations.
Beltstrips and weatherstrips are generally extruded or roll-formed in a complicated manufacturing process having many steps. Typically, a core metal structure is formed and coated with an extruded layer of synthetic elastomeric material to form a belt molding and then is then cut to length. A sealing strip having a flexible blade for contacting the window may be formed and coated in an extrusion process with rubber or similar material to form a base strip. An inner surface of the blade is generally flocked to provide a low friction coating for reducing friction between the blade and the window and to reduce the tendency of the weatherstrip and window to squeak. The sealing strip is usually affixed to the belt molding. The belt molding and the base portion of the sealing strip are usually notched at spaced locations. Clips are then inserted into the notches to affix the belt molding, sealing strip and clips. The clips also grip a flange edge formed on the door of the vehicle to hold the belt weatherstrip to the door of the vehicle.
The materials used to form the belt weatherstrip are typically a combination of thermoset elastomer or thermoplastic and thermoplastic elastomer. For example, an elastomer may be over extruded on a metal carrier and then a post assembled laminate strip of cosmetic film and metal that is roll formed into a C-configuration is mechanically fastened over a section of the front surface of the belt weatherstrip.
The requirement of cosmetic surfaces dictates that the surface area be made of specific thermoplastic, a decorative film, or consist of a painted metal while providing a seal to prevent air and water leakage. Conventional weatherstrips lack the flexibility to interchange the front surface in order to provide a different cosmetic appearance.